JPH06195746A - Optical recording disc - Google Patents

Abstract

PURPOSE:To make an optical recording disc inexpensive and highly reliable by laminating sequentially a recording layer, an intermediate layer and a reflecting layer and, making the intermediate layer contain at least one kind of compound of the metallic elements constituting the reflecting layer. CONSTITUTION:A recording layer 3 mainly composed of a coloring matter is formed on a substrate 2. An intermediate layer 4 is formed on the recording layer 3, and further a reflecting layer 5 is provided on the intermediate layer 4. The substrate 2 is substantiall; formed of glass or resin. Recording and reproduction of data by the recording light and reproducing light is enabled from the rear side of the substrate 2. The intermediate layer 4 contains at least one kind of compound among the metallic elements constituting the reflecting layer 5, and is substantially composed of the compound alone. Because of the presence of the intermediate layer 4, the reflecting layer 5 is not necessary to be formed only of Au and may be selected from metallic elements. An alloy corresponding to the required reflectance or color is used. Accordingly, the intermediate layer 4 eases the potential difference between the recording layer 3 and the reflecting layer 5, preventing a reaction between the coloring matter of the recording layer 3 and the reflecting layer 5, whereby the optical recording disc becomes inexpensive and highly reliable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording disc having a recording layer containing a dye as a main component.

[0002]

2. Description of the Related Art In recent years, various optical recording disks such as a write-once type and a rewritable type have been attracting attention as a large capacity information carrying medium. Among the write-once type optical recording disks, those using a recording layer containing a dye as a main component can be manufactured at low cost because the recording layer can be formed by coating.

As an optical recording disc using a recording layer containing a dye as a main component, a so-called air sandwich structure in which an air layer is provided on the recording layer has been conventionally used, but recently, it is reflected on the surface of the recording layer. An optical recording disk capable of reproducing in compliance with the compact disk (CD) standard has been proposed by providing layers in close contact (Nikkei Electronics January 23, 1989, No. 465, P.
107, Kinki Chemical Society Functional Dye Subcommittee, 198
March 3, 9th, Osaka Science and Technology Center, PROCEEDINGS SP
IE-THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERI
NG VOL.1078 PP80-87, "OPTICAL DATA STORAGE TOPICAL
MEETING "17-19, JANUARY 1989 LOS ANGELES, etc.). This optical recording disc is formed by stacking a dye layer, a reflective layer and a protective film in this order on a transparent substrate, and the reflective layer is adhered to the dye layer. By providing the above, it is possible to configure a CD standard disc having a total thickness of 1.2 mm.

An optical recording disk using a dye in the recording layer is a C
In order to reproduce with a D player, the reflectivity of the Al reflective layer used in a normal CD is insufficient, so the Au reflective layer is used in the above proposal. Au has high reflectance and good corrosion resistance, but is expensive. For this reason, it is considered to use high-reflectance metals other than Au and inexpensive ones, for example, various alloys such as Ag—Cu alloy and Cu—Al alloy.

However, when Cu or a Cu-based alloy is used for the reflective layer, the reaction with the reflective layer constituent material causes deterioration of the dye and a decrease in the recording signal output, so that sufficient reliability cannot be obtained. In particular, since Cu easily chemically reacts with a cyanine dye that is preferably used as a recording layer material, the cyanine dye in the recording layer is likely to deteriorate under high temperature and high humidity. In addition, the cyanine dye is often used as a conjugate with a metal complex quencher or a mixture with it from the viewpoint of light resistance,
Cu easily reacts chemically with the metal complex quencher, and the same problem occurs.

[0006]

DISCLOSURE OF THE INVENTION The main object of the present invention is to realize an optical recording disk having a recording layer containing a dye as a main component, which is inexpensive and highly reliable. .

[0007]

These objects are achieved by the present invention described in (1) to (7) below. (1) Among the metal elements constituting the reflective layer, a recording layer containing a dye as a main component is provided on the substrate, an intermediate layer is provided on the recording layer, and a reflective layer is provided on the intermediate layer. An optical recording disk comprising an intermediate layer containing at least one compound of (2) The thickness of the intermediate layer is 3 to 30 nm (1)
Optical recording disc. (3) The reflective layer is Zn, Sn, Ag, Cu, Ti,
V, Ta, Cr, Mo, W, Mn, Fe, Co, Rh,
The optical recording disc of any one of the above (1) or (2), containing one or more of Ni, Pd, Pt, Au and Al. (4) The optical recording disk according to any one of (1) to (3), wherein the metal element contained in the intermediate layer is contained in the reflective layer in an amount of 1 wt% or more. (5) The optical recording disk according to the above (4), in which the metal element contained in the reflective layer in an amount of 1 wt% or more is contained in the intermediate layer in an amount of 5 wt% or more. (6) The compound of the metal element contained in the intermediate layer is one or more kinds of oxides, nitrides and sulfides.
The optical recording disk according to any one of (5). (7) The above (6), wherein the compound of the metal element is an oxide.
Optical recording disc.

[0008]

The optical recording disk of the present invention is a contact type optical recording disk which has a recording layer containing a dye, an intermediate layer and a reflective layer in this order on a substrate and is compatible with the CD standard.

In the optical recording disc of the present invention, the intermediate layer provided between the recording layer and the reflective layer alleviates the potential difference between the recording layer and the reflective layer, thereby forming a dye or quencher in the recording layer. Since the reaction with the reflective layer is prevented, the deterioration of the dye and the reflective layer and the reduction of the recording signal output can be suppressed, and sufficient reliability can be obtained.

Since the intermediate layer contains the compound of the metal element contained in the reflective layer, the adhesion between the intermediate layer and the reflective layer becomes extremely good.

[0011]

Specific Structure The specific structure of the present invention will be described in detail below.

The optical recording disk of the present invention has an intermediate layer and a reflective layer in close contact with each other on a recording layer containing a dye as a main component,
It is an optical recording disc that can be reproduced according to the CD standard. One embodiment of the optical recording disk of the present invention is shown in FIG.

The optical recording disk 1 shown in FIG. 1 has a recording layer 3 containing a dye as a main component on the surface of a substrate 2, and is in close contact with the recording layer 3 to form an intermediate layer 4, a reflective layer 5 and an organic protective layer. It is a contact-type optical recording disk having a coat 6.

The substrate 2 has recording light and reproducing light (wavelength 60).
It is formed of a resin or glass that is substantially transparent (preferably a transmittance of 88% or more) to a semiconductor laser beam having a wavelength of about 0 to 900 nm, particularly 770 to 800 nm, particularly 780 nm. This enables recording and reproduction from the back side of the substrate.

The substrate 2 is a disk of a normal size, and has a thickness of 1.2 when used as a recordable CD.
The diameter is about 80 mm and the diameter is about 80 to 120 mm.

As the material of the substrate, it is preferable to use a resin, and various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin and TPX are preferable. The substrate 2 may be manufactured by a known method such as injection molding. At that time, it is preferable to form a predetermined pattern such as the groove 21 on the surface of the substrate for tracking or addressing. After the substrate 2 is manufactured, a resin layer having a predetermined pattern such as a groove may be formed by the 2P method or the like.

The groove is preferably a spiral continuous groove having a depth of 500 to 3000 A, a width of 0.2 to 1.1 .mu.m, especially 0.3 to 0.6 .mu.m, and a land (adjacent grooves are adjacent to each other). Portion) width is 0.5-1.
It is preferably 4 μm, particularly 1.0 to 1.3 μm. With such a configuration of the groove, a good tracking signal can be obtained without lowering the reflection level of the groove portion. It should be noted that the groove may be provided with unevenness for address signals. Moreover, it is preferable that the recording light is irradiated onto the recording layer in the groove.

The recording layer 3 may contain only one type of dye, or may have a structure in which two or more types of dyes are compatible with each other.

When recording a CD signal, the extinction coefficient (imaginary part of complex refractive index) k of the recording layer 3 at the wavelengths of recording light and reproducing light is preferably 0.03 to 0.25. When k is less than 0.03, the absorptivity of the recording layer is reduced, and it becomes difficult to perform recording with normal recording power.
Further, when k exceeds 0.25, the reflectance falls below 60%, making it difficult to perform reproduction according to the CD standard. Note that k is 0.03 to 0.20, especially 0.03 to
A value of 0.15 gives very favorable results.

The refractive index (real part of complex refractive index) n of the recording layer 3 is 1.8 to 4.0, and more preferably 2.0 to 4.0.
It is preferably 3.0. When n <1.8, the reflectance is lowered and the signal modulation degree is reduced, which tends to make it difficult to reproduce by a CD player. Further, in order to make n> 4.0, it is difficult to obtain the raw material dye.

The light absorbing dye used for the recording layer 3 has an absorption maximum of 600 to 900 nm, preferably 600 to 900 nm.
800 nm, more preferably 650 to 750 nm,
Other than that, there is no particular limitation, and for example, one or more of cyanine-based, phthalocyanine-based, naphthalocyanine-based, anthraquinone-based, azo-based, triphenylmethane-based, pyrylium or thiapyrylium salt-based, squarylium-based, croconium-based, metal complex dye-based, etc. Two or more kinds may be appropriately selected according to the purpose. As the cyanine dye, a cyanine dye having an indolenine ring which may have an aromatic condensed ring, particularly a benzoindolenine ring is preferable.

The recording layer may contain a quencher, and particularly when a cyanine dye is used, it is preferable that the recording layer contains a quencher. The quencher has a light resistance improving effect. When the quencher is contained, the light absorbing dye may be mixed with the quencher, or an ionic combination of a dye cation and a quencher anion may be used as the light absorbing dye. The quencher is preferably added in an amount of 1 mol or less, particularly 0.05 to 0.5 mol, per 1 mol of the total amount of the light absorbing dye.

The quencher is preferably a metal complex such as acetylacetonate, bisdithio-α-diketone or bisdithiol such as bisphenyldithiol, thiocatechol, salicylaldehyde oxime or thiobisphenolate. . Further, amine compounds having a nitrogen radical cation and amine quenchers such as hindered amines are also suitable.

Of these, cyanine dyes having an indolenine ring are preferred as the dye constituting the conjugate, and metal complex dyes such as bisphenyldithiol metal complex are preferred as the quencher.

Details of preferable dyes, quenchers and binders used in the recording layer are described in, for example, JP-A-59-2.
No. 4692, No. 59-55794, No. 59-5579.
No. 5, No. 59-81194, No. 59-83695,
No. 60-18387, No. 60-19586, No. 60
-19587, 60-35054, 60-36
No. 190, No. 60-36191, No. 60-44554
No. 60, No. 44-5555, No. 60-44389, No. 60-44390, No. 60-47069, No. 60-
20991, 60-71294, 60-548
No. 92, No. 60-71295, No. 60-71296
No. 60, No. 60-73891, No. 60-73892, No. 60-73893, No. 60-83892, No. 60-.
85449, 60-92893, 60-159.
No. 087, No. 60-162691, No. 60-2034.
No. 88, No. 60-201988, No. 60-23488.
No. 6, No. 60-234892, No. 61-16894
No. 61-11292, No. 61-11294, No. 61-16891, No. 61-8384, No. 61-1.
No. 4988, No. 61-163243, No. 61-210
539, Japanese Patent Application No. 60-54013, and Japanese Patent Laid-Open No. 62-3.
No. 1988, No. 62-32132, No. 62-3179.
No. 2, CMC Publishing "Chemistry of Functional Dyes" P74-76
Etc.

The dye used in the recording layer may be selected from the above light-absorbing dyes, dye-quencher mixtures and dye-quencher conjugates having n and k in the above ranges. It may be synthesized by newly designing a molecule.

The k of the dye with respect to the recording light and the reproducing light varies variously from 0 to 2 depending on its skeleton and substituents. Therefore, for example, when selecting a dye having k of 0.03 to 0.25. Is limited in its skeleton and substituents.
For this reason, there are cases in which the coating solvent is limited, or coating cannot be performed depending on the substrate material. Alternatively, vapor phase film formation may not be possible. In addition, a large amount of labor is required for designing and synthesizing a new molecule.

On the other hand, according to the experiments conducted by the present inventors, k of the mixed dye layer containing two or more kinds of dyes is almost equal to the mixing ratio depending on k of the dye layer composed of each dye used. It turned out to be the corresponding value. Therefore, in the present invention, the recording layer 3 may be formed by compatibilizing two or more kinds of dyes.

At this time, k which is almost proportional to the mixing ratio can be obtained in most of the dye mixing systems. That is, i
The mixing fractions and k of the dyes of the species are Ci and ki, respectively.
Then, k becomes almost ΣCiki. Therefore, k
It is possible to obtain a dye layer having k = 0.03 to 0.25 by mixing the dyes having different values with each other while controlling the mixing ratio. Therefore, the dye to be used can be selected from a very wide range of dye groups.

This can also be applied to improve the wavelength dependence. The wavelength of the semiconductor laser is usually in the range of ± 10 nm, and in a commercially available CD player, it is 770 nm to 79 nm.
It is necessary to secure a reflectance of 70% or more in the range of 0 nm. Generally, the k value of a dye has a large wavelength dependency, and even if it is an appropriate value at 780 nm, it often deviates greatly at 770 nm or 790 nm. In such a case, by mixing the second dye, it can be set so that appropriate n and k values are always obtained in the range of 780 ± 10 nm.

As a result, restrictions such as restrictions on the coating solvent are alleviated, and it is possible to use dyes that are easy to synthesize and inexpensive, use dyes having good characteristics, and use dyes that are sparingly soluble. can do.

When the recording layer 3 is a mixed dye layer, the dyes used may be selected from the range of n = 1.6 to 6.5 and k = 0 to 2.

When measuring n and k, a recording layer is formed on a predetermined transparent substrate to a thickness of, for example, 40 to 100 nm under actual conditions to prepare a measurement sample. Next, the reflectance of the measurement sample through the substrate or the reflectance from the recording layer side is measured. The reflectance is measured by specular reflection (about 5 °) using the recording / reproducing light wavelength. In addition, the transmittance of the sample is measured. From these measured values, for example, Kyoritsu Zensho "Optics" Kozo Ishiguro P1
68 to 178, n and k may be calculated.

The recording layer is preferably formed by a spin coating method in which a coating solution containing a dye and an organic solvent is used and the coating solution is spread and coated on a rotating substrate.
As the organic solvent used for the coating liquid for forming the recording layer,
It may be appropriately selected from alcohol-based, ketone-based, ester-based, ether-based, aromatic-based, alkyl halide-based, etc. depending on the dye to be used, but an organic solvent having two or more functional groups in one molecule is It is suitable. After spin coating, the coating film is dried if necessary.

The thickness of the recording layer thus formed is appropriately set depending on the desired reflectance and the like, but is usually about 100 to 300 nm.

In addition to the coating type recording layer, a sheet-shaped or film-shaped recording layer may be used. In this case, the sheet-shaped or film-shaped dye film may be attached to the substrate, or the sheet-shaped or film-shaped dye film itself may be used as the substrate.

An intermediate layer 4 is provided in close contact with the recording layer 3 and a reflective layer 5 is provided on the intermediate layer 4. Middle layer 4
Contains at least one compound of the metal elements forming the reflective layer 5. The intermediate layer 4 preferably consists essentially of this compound.

As the metal element constituting the reflective layer, Z
n, Sn, Ag, Cu, Ti, V, Ta, Cr, Mo,
W, Mn, Fe, Co, Rh, Ni, Pd, Pt, A
It suffices to appropriately select from at least one of u, Al, etc., but in the present invention, since the intermediate layer is provided, it is not necessary to configure the reflective layer with only Au, and therefore a metal other than Au is used for cost reduction. It is preferable to use. When the reflective layer is composed of an alloy, it is sufficient that the intermediate layer contains at least one of the metal elements forming the alloy, and an alloy containing no Au is preferably used.

The metal compound contained in the intermediate layer is an oxide,
It may be either a nitride or a sulfide, but an oxide is particularly preferable.

In such a case, the metal element constituting the metal compound contained in the intermediate layer is contained in the reflective layer in an amount of 1 to 100 wt%,
It is particularly preferable that the content is 2 to 100 wt%. In addition, one or more kinds of compounds of metal elements contained in the reflective layer in an amount of 1 wt% or more are contained in the intermediate layer in a total amount of 5 to 100 wt%,
It is particularly preferable that the content is 10 to 100 wt%.

The specific composition of the reflective layer may be determined according to the required reflectance, color, etc. For example, since the reflectance is high and the color is close to Au, a Cu--Ag alloy or Cu is used. Cu based alloys such as -Al based alloys are preferred. A Cu-Zn alloy can also be used, but since the reflectance is rather low, a high reflectance film such as an Au film may be further formed on the reflective layer to improve the reflectance. In this case, since the Au film may be thin, the cost can be reduced. When these Cu-based alloys are used for the reflective layer, the intermediate layer may be made of a compound such as copper oxide, silver oxide, or zinc sulfide. Furthermore, a reflective film of Ag, Al, Pd, etc. is also preferably used.

To form the intermediate layer 4 and the reflective layer 5,
Various vapor deposition methods such as sputtering may be used. When the sputtering method is used, the same target is used for the intermediate layer and the reflective layer, reactive sputtering is performed by introducing oxygen or nitrogen when forming the intermediate layer, and returned to the Ar atmosphere when forming the reflective layer. By using the method, the intermediate layer and the reflective layer can be continuously formed. When the reflective layer is composed of an alloy of metal A and metal B and the intermediate layer is composed of a compound of metal A, metal A and metal B are used as targets, and only the target of metal A is formed when the intermediate layer is formed. It is possible to continuously form both layers by applying power to the target to perform reactive sputtering and applying power to both targets when forming the reflective layer. However, it goes without saying that a compound target may be used when forming the intermediate layer.

When a material having a relatively high oxygen permeability is used for the substrate 2, the reflective layer 5 is formed in close contact with the recording layer 3, the organic protective coat 6 is further formed, and then the disc is formed. The intermediate layer 4 made of an oxide can be formed by leaving it in an oxidizing atmosphere. This is substrate 2
Oxygen penetrating from the recording layer 3 side through the reflective layer 5
This is because a part of it is oxidized.

The thickness of the intermediate layer 4 is preferably 3 to 30 nm. When the thickness is less than the above range, the effect of suppressing the reaction between the dye and the reflective film becomes small, and when the thickness exceeds the above range, the reflectance is significantly lowered. The thickness of the intermediate layer may be measured by ellipsometry, crystal oscillation measurement, contact step measurement, scanning tunneling electron microscope, or the like.

The thickness of the reflective layer 5 is preferably 60 nm or more. When the thickness of the reflective layer is less than the above range, the strength of the reflective layer tends to be insufficient. There is no particular upper limit to the thickness of the reflective layer, but the thickness need not exceed 200 nm.

With such a reflective layer, the reflectance of the reflective layer alone is 90% or more, and the reflectance (unrecorded portion) through the substrate when the optical recording disk is 60%. Above, especially 70% or more is obtained.

An organic protective coat 6 is preferably provided on the reflective layer 5 as shown in the figure.

The organic protective coat 6 is preferably formed by a spin coating method in order to avoid damage to the reflection layer 5, but a screen printing method, a dipping method, a spray coating method or the like may be used. The conditions for forming the organic protective coat 6 are not particularly limited and may be appropriately determined according to the viscosity of the coating liquid, the target thickness, and the like.

The thickness of the organic protective coat is preferably about 1 to 20 μm. When the thickness is less than the above range,
The effect of the provision tends to be insufficient. When the thickness exceeds the above range, cracks are likely to occur due to shrinkage during curing, and the disc is likely to be warped.

If necessary, the organic protective coat may have a multi-layered structure of two or more layers.

The organic protective coat 6 is preferably composed of a radiation curable resin. Specifically, it is preferably composed of a radiation-curable compound or a substance obtained by radiation-curing a composition for polymerization thereof. Examples of such compounds include acrylic double bonds having unsaturated double bonds that are sensitive to ionization energy and exhibit radical polymerizability, such as acrylic double bonds such as acrylic acid, methacrylic acid, or their ester compounds, and diallyl phthalate. Examples thereof include monomers, oligomers and polymers having or introduced in the molecule a group capable of being crosslinked or polymerized by radiation such as an allyl double bond, an unsaturated double bond such as maleic acid and a maleic acid derivative. These are preferably polyfunctional, particularly trifunctional or more, and may be used alone or in combination of two or more.

The radiation curable monomer has a molecular weight of 2
A compound of less than 000 has a molecular weight of 20 as an oligomer.
Those of 00 to 10,000 are preferable. These include styrene, ethyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, 1,6-hexane glycol diacrylate, 1,6-hexane glycol dimethacrylate, etc., but especially preferred As, pentaerythritol tetraacrylate (methacrylate), pentaerythritol acrylate (methacrylate), trimethylolpropane triacrylate (methacrylate), trimethylolpropane diacrylate (methacrylate), acrylic modified urethane elastomer,
Alternatively, those into which a functional group such as COOH has been introduced, acrylates (methacrylates) of phenol ethylene oxide adducts, acryl groups (methacryl groups) or ε-in the pentaerythritol condensed ring shown in Japanese Patent Application No. 62-072888. Examples thereof include compounds having a caprolactone-acrylic group, and acrylic group-containing monomers and / or oligomers such as special acrylates disclosed in Japanese Patent Application No. 62-072888. Besides this,
Examples of radiation-curable oligomers include oligoester acrylates, acrylic modified urethane elastomers, and those into which a functional group such as COOH is introduced.

In addition to the above compounds, or in place of this, a radiation curable compound obtained by radiation-sensitively modifying a thermoplastic resin may be used. Specific examples of such radiation curable resins include acrylic double bonds having an unsaturated double bond exhibiting radical polymerizability, acrylic double bonds such as methacrylic acid, or ester compounds thereof, and diallyl phthalate. It is a resin in which a group such as an allyl double bond, an unsaturated bond such as maleic acid or a maleic acid derivative, which is crosslinked or polymerized by irradiation with radiation is contained or introduced in the molecule of the thermoplastic resin. Examples of the thermoplastic resin that can be modified into a radiation curable resin include vinyl chloride copolymers, saturated polyester resins, polyvinyl alcohol resins, epoxy resins, phenoxy resins, and fibrin derivatives. Other resins that can be used for radiation-sensitive modification include polyfunctional polyester resins, polyetherester resins, polyvinylpyrrolidone resins and derivatives (P
(VP olefin copolymer), polyamide resin, polyimide resin, phenol resin, spiro acetal resin, acrylic resin containing at least one of acrylic ester and methacrylic ester having a hydroxyl group as a polymerization component are also effective.

Since the coating composition for polymerization is cured by irradiation of radiation, especially irradiation of ultraviolet rays, it is preferable that the composition for polymerization contains a photopolymerization initiator or a sensitizer. The photopolymerization initiator or sensitizer to be used is not particularly limited and may be appropriately selected from usual ones such as acetophenone type, benzoin type, benzophenone type and thioxanthone type. A plurality of compounds may be used in combination as the photopolymerization initiator or the sensitizer. The content of the photopolymerization initiator in the composition for polymerization may be usually about 0.5 to 5% by weight. Such a composition for polymerization may be synthesized according to a conventional method, or may be prepared using a commercially available compound.

As the composition containing the radiation-curable compound for forming the organic protective coat, a composition containing an epoxy resin and a photocationic polymerization catalyst is also preferably used.

The epoxy resin is preferably an alicyclic epoxy resin, and particularly preferably one having two or more epoxy groups in the molecule. As alicyclic epoxy resin,
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4
-Epoxycyclohexylmethyl) adipate, bis-
(3,4-epoxycyclohexyl) adipate, 2-
(3,4-epoxycyclohexyl-5,5-spiro-
One or more of 3,4-epoxy) cyclohexane-meta-dioxane, bis (2,3-epoxycyclopentyl) ether, vinylcyclohexene dioxide and the like are preferable. The epoxy equivalent of the alicyclic epoxy resin is not particularly limited, but 60 to 3 because good curability can be obtained.
00, particularly preferably 100 to 200.

The photocationic polymerization catalyst may be any known one and is not particularly limited. For example, a complex of one or more metal fluoroborate and boron trifluoride,
Bis (perfluoroalkylsulfonyl) methane metal salt, aryldiazonium compound, aromatic onium salt of 6A group element, aromatic onium salt of 5A group element, 3A group
Dicarbonyl chelate of Group 5A element, thiopyrylium salt, MF ₆ anion (where M is P, As or S
Group 6A elements having b), triarylsulfonium complex salts, aromatic iodonium complex salts, aromatic sulfonium complex salts and the like can be used, and in particular, polyarylsulfonium complex salts, aromatic sulfonium salts or iodonium salts of halogen-containing complex ions, 3A It is preferable to use one or more aromatic onium salts of Group 5A group elements and Group 6A elements.

A photocationic polymerization catalyst containing an organometallic compound and a photodegradable organosilicon compound can also be used. Such a cationic photopolymerization catalyst is a non-strong acid type. As the organometallic compound, Ti, V, C
r, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr
A complex compound in which an alkoxy group, a phenoxy group, a β-diketonato group or the like is bonded to a metal atom such as is preferable. Of these, organoaluminum compounds are particularly preferable, and specifically, trismethoxyaluminum, trispropionatoaluminum, tristrifluoroacetylaluminum, and trisethylacetoacetonatoaluminum are preferable.

The organic silicon compound having photodegradability produces silanol upon irradiation with light such as ultraviolet rays,
A silicon compound having a peroxysilano group, an o-nitrobenzyl group, an α-ketosilyl group or the like is preferable.

The content of the photocationic polymerization catalyst in the composition is 0.05 to 0.
It is preferably 7 parts by weight, particularly 0.1 to 0.5 parts by weight.

Among these, it is preferable that a radiation-curable compound having an acrylic group is used, and a coating film containing a photopolymerization sensitizer or an initiator is radiation-cured, especially ultraviolet-cured.

When forming the organic protective coat, the coating film of the composition for polymerization as described above is irradiated with ultraviolet rays to be cured, but in some cases, it may be irradiated with ultraviolet rays after being heated. Instead, it may be irradiated with an electron beam or the like. The intensity of ultraviolet rays applied to the coating film is usually about 50 mW / cm ² or more,
The irradiation dose may be usually about 500 to 2000 mJ / cm ² . Further, as the ultraviolet ray source, a normal one such as a mercury lamp may be used. The above compounds undergo radical polymerization upon irradiation with ultraviolet rays.

The organic protective coat may contain various pigment particles as required.

A label printing layer composed of at least one printing layer may be provided on the organic protective coat 6. The label printing layer is preferably formed by printing a radiation curable resin composition containing various pigments and curing the composition, but other than this, a thermosetting ink may be used.

In order to perform recording or additional recording on the optical recording disc 1 having such a structure, for example, recording light of 780 nm is used.
Irradiation is performed in a pulse shape through the substrate 2 to change the light reflectance of the irradiation portion. When the recording light is irradiated, the recording layer 3 absorbs the light and generates heat, and at the same time, the substrate 2 is also heated. As a result, in the vicinity of the interface between the substrate 2 and the recording layer 3, the recording layer material such as a dye is melted or decomposed, pressure is applied to the interface between the recording layer 3 and the substrate 2, and the bottom surface or side wall of the groove is deformed. Sometimes.

[0066]

EXAMPLES The present invention will be described in more detail below by showing specific examples of the present invention.

An optical recording disk sample having the structure shown in FIG. 1 was prepared.

As the substrate 2, a polycarbonate resin plate having a spiral continuous groove and a diameter of 120 mm and a thickness of 1.2 mm was used.

The recording layer 3 was formed by spin coating.
The coating liquid used for forming the recording layer 3 contains a dye and an organic solvent, and as the dye, the dye A of the following chemical formula 1 is used.
1 and A2 and a singlet oxygen quencher were used. The A1 content in the dye is 60% by weight, and the A2 content is 3
0% by weight, singlet oxygen quencher content is 10% by weight
And

[0070]

[Chemical 1]

As the singlet oxygen quencher, Q1 (Cu complex) or Q2 (Ni complex) shown below was used.

[0072]

[Chemical 2]

Diacetone alcohol was used as the organic solvent. The pigment content in the coating liquid was 5% by weight. The thickness of the recording layer was 200 nm.

The intermediate layer 4 is made of copper oxide, chromium oxide or silver oxide and is formed by a sputtering method using a compound target.

The reflective layer 5 is made of Cu-Ag alloy, Ag-Cr.
The alloy or Ag was used and formed by the sputtering method.

The organic protective coat 6 was formed by applying a UV-curable resin (SD-17, manufactured by Dainippon Ink & Co., Ltd.) by spin coating and curing it with UV rays. The thickness of the organic protective coat after curing was 5 μm.

For comparison, a sample without the intermediate layer 4 was also prepared.

The constitution of each layer of each sample is shown in Table 1 below.
Shown in.

Each of the above samples was reproduced on a commercially available compact disc player, and the BLER (block error rate) was measured. Also, 80 ° C, 80% R
The same measurement was carried out after 100 hours of storage in the H environment. The results are shown in Table 1. BLER was measured for 10 minutes, and the average value per second was shown. The BLER CD standard is 220 (counts / second) or less.

[0080]

[Table 1]

From the results shown in Table 1, the effect of the present invention is clear.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an example of an optical recording disk of the present invention.

[Explanation of Codes] 1 Optical recording disk 2 Substrate 21 Groove 3 Recording layer 4 Intermediate layer 5 Reflective layer 6 Organic protective coat

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Doi 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation

Claims (7)

[Claims] 1. A metal element that comprises a recording layer containing a dye as a main component on a substrate, an intermediate layer on the recording layer, and a reflective layer on the intermediate layer, which constitutes the reflective layer. An optical recording disc, characterized in that the intermediate layer comprises at least one compound of 2. The optical recording disk according to claim 1, wherein the intermediate layer has a thickness of 3 to 30 nm. 3. The reflective layer comprises Zn, Sn, Ag, Cu,
Ti, V, Ta, Cr, Mo, W, Mn, Fe, Co,
3. The optical recording disk according to claim 1, containing at least one of Rh, Ni, Pd, Pt, Au and Al. 4. The optical recording disk according to claim 1, wherein the metal element contained in the intermediate layer is contained in the reflective layer in an amount of 1 wt% or more. 5. The optical recording disk according to claim 4, wherein the metal element contained in the reflective layer in an amount of 1 wt% or more is included in the intermediate layer in an amount of 5 wt% or more. 6. The optical recording disk according to claim 1, wherein the compound of the metal element contained in the intermediate layer is at least one kind of oxide, nitride and sulfide. 7. The optical recording disk according to claim 6, wherein the compound of the metal element is an oxide.